You only have to end a few minutes on the internet to find out Thai Airways has declined in service and affordability over the last few years. Once a great Airline now cr*p.
Immigration in Thailand is not like 7/11 stores which are consistant with their service. Every Immigration office has their own spin on policies and proceedures. Your question is like asking," How long is a piece of string".
First mistake, using B Quick for mechanical repairs. Very few real mechanics in this country, a lot of back yard boys pretending to be Mechanics. Use a well establised dealership with mechanical workshop facilities.
I feel ashamed that this guy comes from Australia, a real scumbag, the Tai driver more than likely caused this outburst, however, no excuse for carrying on like that.